1. Field of the Invention
The present invention relates to an improved injection molding machine with a stack mold carrier. More particularly, the present invention relates to a stack mold carrier for an injection molding machine wherein the services to a rotating turret is provided by a rotary union at the pivot of the stack mold.
2. Related Prior Art
Stack mold systems for molding articles are well known in the prior art. Early stack mold carriers were attachments to the mold center section that supported it in the molding machine and allowed the center section to slide along the machine""s tiebars. U.S. Pat. No. 4,408,981 to Brown shows a carrier riding on the lower tie bars. Removal of the mold required the removal of the carrier as they were not attached to the machine.
Another such stack mold is shown in U.S. Pat. No. 5,707,666 to DiSimone et al. The ""666 Patent stack mold system has a unique linkage arrangement whereby a center section and a movable end platen is displaced from the stationary platen at different rates, thereby opening and closing the stack mold during the injection molding process. In this patent, the center section does not rotate, but only translates away from the fixed platen.
Turret style molding machines are also well know in the prior art. A turret style molding machine includes a center or end platen that rotates following an injection cycle to either align with a post-molding operation (ie, cooling, forming, etc.) or with another injector in a multi-material application. U.S. Pat. No. 4,427,359 to Fukuoka discloses an injection stretch blow molding machine. The machine incorporates a four sided turret block positioned on a vertical axis wherein preforms are injection molded in a first position of the four sided turret block. Preforms are temperature conditioned inside a second conditioning mold at a second position of the block. The preforms are blow molded at a third position and ejected at a fourth.
U.S. Pat. No. 4,243,362 to Rees discloses a composite molding apparatus for molding articles from two materials. The apparatus includes a four sided turret block rotatable between two opposed faces about a horizontal axis. The block is mounted slidably between a fixed and a moving platen of a horizontal injection molding machine. Two material molding is achieved by injecting different materials from separate injectors when the block is in each of the two positions.
U.S. Pat. No. 5,728,409 to Schad et al., teaches a turret style injection molding machine having a rotating and longitudinally movable turret block with a plurality of mold halves rotatable and movable into engagement with a non-rotatable mold half and at least one additional molding related operation. Services to the rotating turret block are provided by a rotary union located at the axis of rotation of the turret block.
U.S. Pat. No. 4,734,023 to Nesch et al. discloses a turret style injection molding machine in a stack mold configuration. The turret rotates in 90xc2x0 intervals to align with a first and second injector. This apparatus uses two fixed platens and a movable platen in communication with the rotating turret. The movable platen is connected to the fixed platens via a plurality of tiebars which also support and guide the platens. The movable platen and turret are operated by an inline hydraulic cylinder.
There exists a need for an improved stack mold injection molding machine that provides a rotating turret where services are provided to the rotating turret through a rotary union. In addition, it is desirable to incorporate features in conjunction with a rotary turret whereby the mold may be removed without the removal of the tiebars.
The primary objective of the present invention is to provide an improved stack mold injection molding machine with a rotating turret.
Another object of the invention is to provide a means for providing services like water, hydraulic oil, pressurized air, electrical power, etc. to the rotating turret of a stack mold injection molding machine.
A further object of the present invention is to provide a stack mold injection molding machine with a drive means for selectably rotating a turret.
Yet another object of the present invention is to provide a stack mold injection molding machine with a rotating turret whereby turret rotation is independent of the clamp motion.
Still yet another object of the present invention is to provide a stack mold injection machine that reduces the mold open time and allows for part removal from the top or the bottom of the rotating turret.
Yet another object of the present invention is to provide a rotating turret in a stack mold injection machine that eliminates swinging hoses and electrical cables by the use of a rotary union.
The foregoing objects are achieved by the present invention which comprises a pair of mold supports to which the rotating turret can be attached. Each mold support is movable along a linear rail attached to the base of a molding machine and has at least one block containing a linear bearing mounted thereto for engaging the linear rail. Each mold support further includes a linkage assembly for connecting the mold support to other platens to synchronize movement of each mold support with movement of at least one other platen. Rotatably attached between a pair of mold supports is a turret which comprises at least one mold cavity for interface with at least one platen. Attached to at least one mold support is an actuator like an electric servomotor and in communication with the turret for rotation about a central axis. Provided to the rotating turret through the central axis of rotation is a rotary union for the communication of various services like oil, water, air, electrical power, etc.
Other details of the present invention, as well as other objects and advantages attendant thereto are set forth in the following detailed description and the accompanying figures, in which like reference numerals depict like elements.